interesting, I just tried it with your slider on your site Brice and I'm seeing the same exact thing.... If you try to grab and slide the thumb quickly it will often slide to the next item in the carousel. I have an iPad 3 with iOS 6, can you tell me what your version of iPad is?

I have an iPad 2 running iOS 5.1. I even tried to do some really quick motions, blurring the line between swiping and dragging and it still worked.

I will say though that I can make it trip up occasionally when the thumb is at one of the extreme ends of the slider. But even then it's rare.

If this is still a problem I would recommend stepping back from creating your custom slider component and concentrate on potentially managing the events (stopping/suspending events) while using the built-in components. Once the core problem is solved you can always go back and hook in your custom component.